Sports Mufflers

[jjwithers]

While this topic is being bounced around.... what about these guys?
They are Untitled Motorcycles in the UK. They are making custom BMWs and they have a bunch of bikes that have a straight pipe and no muffler.

From what i understand, they could be sacrificing some top end power as a result?

[twist]

Josh, thanks for the photos of the rebuilt bike. A good friend gave me a 78 R100RS Motosport that is a basket case. No fairing but engine block and frame with matching numbers as well as a great set of snow flake wheels and other parts but the bike was not whole. They, (my friends), loaded up into my wife's car as I was trying to figure out a way to hide it from her. All the way home I was trying to figure out how they managed to get the bike in the car before I knew what was happening. Got the bike home and hid it amongst my other bike stuff. Eventually it was discovered by her but she did grasp the notion of it being a Motosport. So now I have my project. I can see it's going to take lots of time and money. I know Dave at Recommended Service. He's done work for me and helped me with the wheels recently. The Motosport frame and swing arm have been braced by CC products, (in the '70s I presume). I admire your tenacity in building your bike, it seems a daunting project but obsession runs deep.

[vanzen]

...From what i understand, they could be sacrificing some top end power as a result?

From what I understand
they will be sacrificing mid-range torque, top-end HP, the exhaust valves,
and very likely their hearing ...

[Sam LP]

Untitled Motorcycles: I think there is a peashooter silencer on their bikes, but the headers are very short. I think what Vanzen says still applies in this case.

[lomax]

I had a set of actual 1984 Super Trap exhaust on my bike when I bought it. Alas they cam off so that a Brown side stand could go on.

The bike runs just as good with the stock system on but is a lot quieter, ahhhhh !




Marc

[SteveD]

Can anyone id these?

http://www.youtube.com/watch?v=0DdP4PWL ... re=related

[chasbmw]

They look like Dunstall silencers as fitted to nortons in the 60s and 70s.

[Major Softie]

Supertrapps are tunable (how many discs you put on the end), so they can be very quiet to very loud, with many many steps in-between. I've had a couple bikes with them.

[Ken in Oklahoma]

Supertrapps are tunable (how many discs you put on the end), so they can be very quiet to very loud, with many many steps in-between. I've had a couple bikes with them.

I've always been prejudiced against Supertrapps, seeing them as gimmicky and probably not the best way to achieve a certain desired power band without excessive compromise of other part of the power band, whether it be more torque or more high end power.

Do you (or anybody else) have a good opinion of them?


Ken

[Major Softie]

Supertrapps are tunable (how many discs you put on the end), so they can be very quiet to very loud, with many many steps in-between. I've had a couple bikes with them.

I've always been prejudiced against Supertrapps, seeing them as gimmicky and probably not the best way to achieve a certain desired power band without excessive compromise of other part of the power band, whether it be more torque or more high end power.

Do you (or anybody else) have a good opinion of them?


Ken

Having the ability to tune back-pressure certainly can be an advantage. I've found that they are conceptually sound, and well built. On the other hand, I haven't found (in years past) that they were particularly well designed for specific motor applications. That is, their megaphone designs didn't seem designed for the greatest performance for each motor, so they tended to be inconsistent between different vehicles in whether or not they offered real performance gains. My most recent was on a Suzuki DR350, which had to be pretty loud to realize the best performance, but it did perform well and increased power throughout the rev range. My 82 GPZ750 had one, and I didn't find any noticeable performance increase, but it did take about 20 lbs. off the bike.

The new ones may be more carefully designed for each motor, or they may not. I don't know.